The problem started when I was trying to download the 12.04 Beta 1 but didn't have sufficient time to complete the install. As I try to upgrade or re-download 12.04 I get the message "Not all updates can be installed" with the choice to Partial Upgrade or close.
Partial Upgrade gives me:
An upgrade from 'precise' to 'oneiric' is not supported with this tool.
Close gives me:
Software index is broken
It is impossible to install or remove any software. Please use the package manager "Synaptic" or run "sudo apt-get install -f" in a terminal to fix this issue at first.
The Synaptic suggestion doesn't work as well. The command gives me
E: dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem.